New Studies on Omicron: Variant Multiplies at Slower Rate in Lungs
2021-12-21
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1The Reuters news agency recently examined a group of new studies on COVID-19.
2These studies, for the most part, have yet to be closely examined by outside experts.
3They include information that needs further study to support their findings.
4Researchers said last week that differences in how well Omicron and other variants of the coronavirus multiply may help predict Omicron's effects.
5Compared to the earlier Delta variant, Omicron multiplies itself 70 times more quickly in tissues that line airway passages.
6This may speed up person-to-person spread, the researchers said.
7But in lung tissues, Omicron multiplies 10 times more slowly than the original kind of the coronavirus.
8This difference might lead to less-severe illness.
9An official report of these findings is under careful study by a group of experts before publication and has not been released by the research team.
10In a news release issued by Hong Kong University, study leader Dr. Michael Chan Chi-wai said,
11"It is important to note that the severity of disease in humans is not determined only by virus replication"
12but also by each person's immune response to the infection.
13Such a response sometimes turns into life-threatening inflammation.
14Chan added, "By infecting many more people, a very infectious virus may cause more severe disease and death even though the virus itself may be less pathogenic."
15Pathogenic is a term that describes something such as a type of bacteria or a virus that causes disease.
16Chan explained further, "taken together with our recent studies showing that the Omicron variant can partially escape immunity from vaccines and past infection,
17the overall threat from Omicron variant is likely to be very significant."
18Another group of researchers said a model of how the Omicron variant attaches to cells and antibodies gives information about its behavior and will help in designing treatments.
19Using computer models of the spike protein on Omicron's surface,
20they examined changes occurring when the spike grabs onto a cell-surface protein called ACE2, the virus' way into the cell.
21The research team also modeled the spike with different classes of antibodies trying to attack it.
22The antibodies attack from different places, "like a football team's defense might tackle a ball carrier,"
23 said Joseph Lubin of Rutgers University in New Jersey.
24The findings, posted last week on the website bioRxiv ahead of examination by outside experts, need to be checked,
25 "particularly with real-world samples from people," Lubin said.
26He added "while our molecular structure predictions are by no means a final word on Omicron,
27(we hope) they enable a faster and more effective response from the global community."
28A third study, put online last week in the publication JAMA Network Open,
29showed that infected people who show no symptoms might be helping to spread SARS-CoV-2, the virus that causes COVID-19.
30Such cases, known as asymptomatic cases, could make up to 40.5 percent of confirmed infections worldwide.
31Researchers grouped data from 77 earlier studies involving a total of 19,884 individuals with confirmed SARS-CoV-2 infections.
32They found that among infected people in the general community,
33about 40 percent were asymptomatic, as were 54 percent of infected pregnant women, 53 percent of infected air or cruise travelers,
34 48 percent of infected nursing home residents or staff and 30 percent of infected healthcare workers or hospitalized patients.
35The grouped percentage of asymptomatic infections was about 46 percent in North America, 44 percent in Europe and 28 percent in Asia.
36Min Liu and other researchers at Peking University in China wrote "the high percentage of asymptomatic infections highlights" the possible spread risk of "asymptomatic infections in communities."
37The researchers added that officials should check for asymptomatic infections,
38and those who are identified "should be under management similar to that for confirmed infections, including isolating and contact tracing."
39I'm John Russell.
1The Reuters news agency recently examined a group of new studies on COVID-19. These studies, for the most part, have yet to be closely examined by outside experts. They include information that needs further study to support their findings. 2Omicron grows faster in airways, slower in lungs 3Researchers said last week that differences in how well Omicron and other variants of the coronavirus multiply may help predict Omicron's effects. 4Compared to the earlier Delta variant, Omicron multiplies itself 70 times more quickly in tissues that line airway passages. This may speed up person-to-person spread, the researchers said. But in lung tissues, Omicron multiplies 10 times more slowly than the original kind of the coronavirus. This difference might lead to less-severe illness. 5An official report of these findings is under careful study by a group of experts before publication and has not been released by the research team. In a news release issued by Hong Kong University, study leader Dr. Michael Chan Chi-wai said, "It is important to note that the severity of disease in humans is not determined only by virus replication" but also by each person's immune response to the infection. Such a response sometimes turns into life-threatening inflammation. 6Chan added, "By infecting many more people, a very infectious virus may cause more severe disease and death even though the virus itself may be less pathogenic." 7Pathogenic is a term that describes something such as a type of bacteria or a virus that causes disease. 8Chan explained further, "taken together with our recent studies showing that the Omicron variant can partially escape immunity from vaccines and past infection, the overall threat from Omicron variant is likely to be very significant." 9Omicron holds cells more tightly, withstands some antibodies 10Another group of researchers said a model of how the Omicron variant attaches to cells and antibodies gives information about its behavior and will help in designing treatments. 11Using computer models of the spike protein on Omicron's surface, they examined changes occurring when the spike grabs onto a cell-surface protein called ACE2, the virus' way into the cell. 12The research team also modeled the spike with different classes of antibodies trying to attack it. The antibodies attack from different places, "like a football team's defense might tackle a ball carrier," said Joseph Lubin of Rutgers University in New Jersey. 13The findings, posted last week on the website bioRxiv ahead of examination by outside experts, need to be checked, "particularly with real-world samples from people," Lubin said. He added "while our molecular structure predictions are by no means a final word on Omicron, (we hope) they enable a faster and more effective response from the global community." 14Four in 10 infected people may unknowingly spread virus 15A third study, put online last week in the publication JAMA Network Open, showed that infected people who show no symptoms might be helping to spread SARS-CoV-2, the virus that causes COVID-19. Such cases, known as asymptomatic cases, could make up to 40.5 percent of confirmed infections worldwide. 16Researchers grouped data from 77 earlier studies involving a total of 19,884 individuals with confirmed SARS-CoV-2 infections. They found that among infected people in the general community, about 40 percent were asymptomatic, as were 54 percent of infected pregnant women, 53 percent of infected air or cruise travelers, 48 percent of infected nursing home residents or staff and 30 percent of infected healthcare workers or hospitalized patients. 17The grouped percentage of asymptomatic infections was about 46 percent in North America, 44 percent in Europe and 28 percent in Asia. 18Min Liu and other researchers at Peking University in China wrote "the high percentage of asymptomatic infections highlights" the possible spread risk of "asymptomatic infections in communities." 19The researchers added that officials should check for asymptomatic infections, and those who are identified "should be under management similar to that for confirmed infections, including isolating and contact tracing." 20I'm John Russell. 21Nancy Lapid reported on this story for Reuters. John Russell adapted it for Learning English. Susan Shand was the editor. 22_____________________________________________________________ 23Words in This Story 24multiply - v. to increase greatly in number or amount : to become much more numerous 25replication -- n. to repeat or copy (something) exactly 26inflammation -- n. a response to cellular injury that serves as a mechanism to eliminate harmful agents and damaged tissue 27significant -- adj. very important 28model -- n. A system of data presented as a mathematical description of something 29tackle -- v. to try to get the ball from (an opposing player who has it); American football or rugby : to force (the player with the ball) to fall to the ground